1. Field of the Invention
This invention relates to a radio telephone system control apparatus and a method for controlling the connection of a master apparatus connected to a wired telephone channel and a plurality of radio telephone sets connected by radio channels to the master apparatus, and more particularly to an apparatus for controlling the connection in response to the origination of a call by any one of the plurality of the radio telephone sets.
2. Description of the Related Arts
Among radio telephone systems comprising a master apparatus connected to wired telephone channels and one or more radio telephone sets connected to the master apparatus through radio channels may be mentioned a so-called cordless telephone apparatus, for example. A cordless telephone apparatus comprises a master apparatus connecting apparatus connected to wired telephone channels, and a wireless telephone set provided for the master apparatus in a one to one correspondence, and the frequencies of its signals are fixed such that up radio channels from the radio telephone sets to the master apparatus utilizes signals of frequency f.sub.1, while down telephone channels from the master apparatus to the radio telephone sets utilize signals of frequency f.sub.2. As a consequence, where two radio telephone sets are utilized, it is necessary to install two master apparatus.
With such a radio telephone system utilizing two radio telephone sets and two master apparatus, however, two radio telephone sets are not usually used simultaneously, so that provision of two master apparatus is not economical.
In recent years, for the purpose of efficiently utilizing allocated frequencies, multi-channel access systems have been adopted wherein a frequency being used is determined by utilizing a common channel, for example, a control channel among a plurality of master apparatus, and then the channel is switched to a speech channel corresponding to the frequency. However, when such a multi-channel access system is used there is a problem when either one of two radio telephone sets originates a call, or in what manner the channel should be switched to the speech channel. Furthermore, where more than two wired telephone sets are connected to one master apparatus, there is a problem in selecting the wired telephone channel to which the master apparatus should be connected.